Submicroscopic unbalanced translocation resulting in del10p/dup13q detected by subtelomere FISH.

Chromosomal rearrangements involving the (sub)telomeres are an important cause of human genetic diseases: with the development of advanced molecular cytogenetic methods they have been identified as a major cause of mental retardation and/or congenital malformation syndromes. We identified a cryptic unbalanced de novo translocation 10p/13q by subtelomere FISH in a boy with mental and growth retardation (karyotype: 46,XY,der(10)t(10;13)(p15.1;q34)(D10S2488-,D13S296+)). Craniofacial dysmorphisms included frontal bossing, epicanthal folds, long philtrum, thin upper lip, short nose, mild retrognathy and a flat midface. In addition the patient had ASDII, a pyloric stenosis, bilateral inguinal hernias and cryptorchidism. His psychomotor development was significantly delayed. Microsatellite typing revealed the paternal origin of the two chromosomes involved in the rearrangement. By comparing our case with previously published patients with similar aberrations we conclude that the congenital malformations in our case are associated with the partial 10p deletion. The craniofacial features might be attributed to the 13q duplication. The identification of a 10p/13q translocation in our case highlights the importance of searching for cryptic subtelomeric imbalances in mentally retarded patients and helps to further delineate genotype-phenotype correlations in rare chromosomal disturbances.

Chromosomal aberrations in 130 patients with multiple myeloma studied by interphase FISH: diagnostic and prognostic relevance.

The study described the molecular cytogenetic characterization of myeloma cells in 130 patients via interphase fluorescence in situ hybridization. Nine repetitive DNA probes (for chromosomes 3, 7, 9, 11, 15, 17, 18, X, and Y) as well as seven single-copy DNA probes (for chromosomes 13, 17, 21, and two each for chromosomes 5 and 22) were used for the hybridizations. Using this panel of probes, we were able to show aberrations in 86% of patients. Most of them had one to three aberrations. There was a distinct correlation between the number of aberrations per patient and the tumor stage. Thus, the proportion of patients with 8-12 aberrations increased from 16% in stage II to 26% in stage III. There were marked differences among the chromosomes with respect to the prevalence of genomic losses and gains and deletions of gene loci. Chromosomes 3, 5, 7, 9, 11, 15, and 21 showed a preference for genomic gains. Losses were most often found for chromosomes 13 and 17 (locus specific) as well as for the X and Y chromosomes. The frequency of monosomies and trisomies were approximately the same for chromosomes 15 and 18, which indicates a skewed pattern of distribution. We found two specific aberrations that caused distinct changes in the survival rates of the patients: deletion 13q14 (28% of patients) and translocation of the IGH locus 14q32 (79% of 39 patients who were analyzed separately). The results obtained in this study yielded data of extremely relevant prognostic value.

Identification of supernumerary der(20) chromosomes by FISH in three patients.

Small supernumerary marker chromosomes of 3 patients were characterized at the molecular cytogenetic level. Two ring chromosomes and one metacentric marker were shown to be distamycinA/DAPI-negative and did not possess satellite regions after conventional banding techniques. Fluorescence in situ hybridization (FISH) was performed and in all 3 cases the supernumerary markers were shown to be derived from chromosome 20. Phenotypes are described and discussed with respect to karyotypes. Two of the patients are developmentally and/or phenotypically normal. The first patient has a ring chromosome, containing a small amount of euchromatic material; the second patient is the carrier of a small, metacentric and most probably heterochromatic marker. Patient 3 has physical anomalies, including a congenital heart defect and delayed motor development, but is intellectually almost normal. His marker chromosome is a ring containing a small amount of euchromatic material.

Report of two new cases of Pallister-Killian syndrome confirmed by FISH: tissue-specific mosaicism and loss of i(12p) by in vitro selection.

Tissue-specific mosaic distribution of an additional isochromosome 12p is the characteristic chromosomal aberration in Pallister-Killian syndrome. Often it is confined to fibroblasts, whereas lymphocytes show a normal karyotype. Two cases are reported in which the distribution of the additional i(12p) was analysed in various tissues. The isochromosomes were characterised by conventional banding technics and fluorescence in situ hybridization (FISH). In the first case, diagnosed prenatally, 4 different tissues were analysed. A direct preparation of chorionic villi (21 gestational weeks) showed an extra marker chromosome in 19% and two additional copies in 3% of the examined cells. In two cultures of amniocytes (17 and 21 weeks), the i(12p) was observed in 23% and 12%, respectively. It was absent in cultured lymphocytes of fetal blood (21 weeks). The fibroblast long-term culture of umbilical cord showed the i(12p) in 100% of metaphases. In the second case of a term infant the i(12p) was diagnosed in cultured lymphocytes (4%) and fibroblasts (93%). Secondary loss of the isochromosome was evaluated by in vitro selection in case 2 analysing metaphases and interphases of fibroblasts in the 1st, 4th and 5th subculture using FISH. The proportion of cells with i(12p) decreased from 93% to 40% and to 28%, respectively. DNA analysis in case 1 showed a maternal meiotic origin of the i(12p). The prenatally detected clinical findings in both cases showed characteristic abnormalities of the Pallister-Killian syndrome.

Distal 2q duplication: report of two familial cases and an attempt to define a syndrome.

Two cases of partial trisomy 2q are described, both resulting from a balanced translocation in one of the parents. In one case the chromosomes 2 and 11 were involved [paternal karyotype: 46,XY,t(2;11)(q33;q23)]; in the second case, chromosomes 2 and 8 [paternal karyotype: 46,XY, t(2;8(q32;p23)]. When the two patients were compared to the few cases reported in the literature, it was concluded that the associated clinical syndrome is characterized by severe psychomotor retardation and relatively mild abnormalities involving skull and facies.

Klinefelter's syndrome and mitral valve prolapse. an echocardiographic study in twenty-two patients.

It is well known that the incidence of mitral valve prolapse is increased in various hereditary and humoral disorders, particularly in diseases with abnormal collagene structure and metabolism. We consecutively investigated, both clinically and echocardiographically, 22 patients with Klinefelter's syndrome (Mean age: 35 +/- 15.8 years). On clinical examination one third (7 patients) showed clinical signs of connective tissue weakness, 9 patients were obese. In 3 patients without a history of rheumatic fever mitral regurgitation was present. A mid-systolic click was heard in 12 patients, in 8 of them a click-murmur syndrome. Mitral regurgitation has been found in 3 patients. Echocardiographic ally, 12 of 22 patients (55%) revealed mitral valve prolapse which was not correlated with the degree of the chromosomal aberration. The incidence of mitral valve prolapse in an otherwise healthy male population is reported to be approximately 6%. Thus, in Klinefelter's syndrome, the frequency of mitral valve prolapse is found to be markedly increased. Regarding the nosological implications of mitral valve prolapse, it is recommended to thoroughly examine patients cardiologically. Furthermore, since mitral valve prolapse bears a higher risk of malignant cardiac arrhythmias, chest pain and endocarditis, an antiarrhythmic treatment and--if indicated--antibiotic prophylaxis has to be instituted. Those patients also should be advised to adjust their life style appropriately.

A new possible parameter for the detection of aneuploidy inducing substances: the analysis of qualitative and quantitative abnormalities of the spindle apparatus.

In the present study, compared to other cytogenetic methods, we measured the number of aneuploid cells directly by analyzing anomalies of the mitotic spindle. Qualitative and quantitative abnormalities of the mitotic spindle apparatus in transformed and non-transformed cell lines in vitro were classified. We treated the different cell lines with well known aneugenic agents as Benomyl and Griseofulvin and investigated the mitotic spindle under different experimental conditions. The spindle apparatus was stained by indirect immunofluorescence and the chromatin was counterstained by fluorescent dyes. The mitotic spindle showed a great sensitivity to the aneuploidy-inducing substances used in our experiments. The spindle-disturbing effect of the tested substances was demonstrated to be dose- dependent. The morphological alterations appeared to be independent of the aneuploidy-inducing test substance used, but showed a relation to the dose and length of treatment. Thus, the analysis of the mitotic spindle may be a useful screening parameter for the detection of aneuploidy-inducing substances and further investigations will provide additional results to specific parameters.

Cytogenetic and andrological status and ICSI-results in couples with severe male factor infertility.

AIM: To pursue whether cytogenetic aberrations correlate with specific spermatological or hormonal abnormalities. METHODS: 305 infertile couples were investigated. All male partners were referred to a complete andrological work-up with physical examination, determination of hormones, HIV testing and semen analysis. Cytogenetic analysis was carried out in both partners by means of standard techniques using cultured lymphocytes from peripheral blood. RESULTS: Among the 305 couples, 10 men (3.2%) and 10 women (3.2%) showed constitutional chromosomal aberrations, including reciprocal translocations (n = 7), Robertsonian translocations (n = 3), inversions (n = 3), other structural aberrations (n = 4) and sex chromosome aberration (n = 3). In addition to the impaired sperm count in most of the patients, a tendency to an increased proportion of spermatozoa with acrosome defect was observed. CONCLUSION: Chromosomal aberrations may contribute to the low fertilization and pregnancy rates in the infertile couples.

Prenatal diagnosis and management in fetuses with cystic hygromata colli.

We report on 45 fetuses with prenatally diagnosed bilateral cystic hygromata colli by ultrasound. Two of the 45 cases involved a twin pregnancy with only one fetus showing hygromata colli. In 2 cases there was only isolated hygromata colli. The other 43 cases showed the signs of non-immune hydrops fetalis. The cytogenetic findings were: 9 fetuses with Turner syndrome, 1 fetus with Turner mosaicism, 1 fetus with trisomy 18, 6 fetuses with trisomy 21, 12 fetuses with normal karyotype, and 16 fetuses with a failed chromosome culture. In fetuses with Turner syndrome and normal karyotype the sonographic findings were similar: massive bilateral hygromata colli, substantial fluid accumulations in skin and body cavities, oligohydramnios and intra-uterine growth retardation. In the cases with trisomy 21, the relative size of the hygromata colli was smaller. Intra-uterine growth retardation and oligohydramnios were not observed. The sole survivor of our group (elective pregnancy interruption: 30 cases; intra-uterine death: 14 cases) (karyotype: 46,XY) presented sonographically with massive ascites, a moderate cystic hygroma, and appropriate fetal development, and a normal amniotic fluid quantity. These findings are analysed in order to provide recommendations for prenatal diagnosis, prenatal management and genetic counselling of the couples concerned.

Combination of hypospadias and maldescended testis as cardinal symptoms in gonosomal chromosome aberrations.

Intersexual genitals or distinct hypospadias in combination with maldescended testis can be caused by endocrinological as well as chromosomal abnormalities. Even in early childhood such clinical findings require specific diagnostic procedures and subsequent treatment which is often invasive but has special importance as regards the early diagnosis of gonadal tumors. We present a child with cryptorchidism on the right, inguinal testis on the left and penoscrotal hypospadias. Cytogenetic analyses revealed a mosaic karyotype 45, X/46, X, idic (Yp) with unequal distribution of the mosaic in different tissues. In consequence of this chromosomal aberration the patient had mixed gonadal dysgenesis which is associated with an increased risk of tumor development in the aberrant gonads. The principles of pediatric, urological, cytogenetic and endocrinological diagnostics and the mode of data collection in the presented case are described and discussed. Furthermore, a protocol for preventive screening is presented, which combines urological and endocrinological investigations in males with malformations of the genito-urinary tract to minimize the risk of tumor development in the aberrant gonads.

[Uniparental disomy 7 in the pathogenesis of Silver-Russell syndrome]. / A 7-es kromoszóma uniparentalis disomiája a Silver-Russel-syndroma kóreredetében.

The authors report the frequency and the clinical signs of uniparental disomy of chromosome 7 in Silver-Russell syndrome patients. A cohort of 73 families were typed with Short Tandem Repeat markers from chromosomes 7. In 6 patients maternal uniparental disomy 7 (UPD7) was detected. Summarising their data and those from the literature, an overall frequency of maternal uniparental disomy 7 of approximately 10% can be estimated. Allelic distribution in two of their maternal uniparental disomy 7 families indicates complete isodisomy whereas allelic patterns in the other four families are consistent with partial and complete heterodisomy, respectively. The clinical features of maternal uniparental disomy 7 patients do not show any deviation from the non-uniparental disomy 7 patients. Additionally, there was not hint for possible influences of iso- or heterodisomy, possibly associated with different stages of mosaicism. Their results demonstrate the necessity to screen SRS patients for UPD7 although the effect of UPD7 cannot be correlated to the SRS phenotype yet. Furthermore, an association between UPD for chromosomes other than 7 and SRS seems to be negligible. Vice versa, maternal UPD7 is not detectable in non-SRS patients. Therefore, testing for maternal UPD7 can be restricted to SRS families, searching for other UPDs in this population does not seem to be reasonable. Additionally, cytogenetic analysis should also be performed in SRS patients: identification of commonly involved chromosomal regions should allow narrowing down a SRS-relevant region.

[Aberrations of chromosome 18 and their significance in genetic counseling]. / A 18-as kromoszóma rendellenességeinek eredete és jelentósége a genetikai tanácsadásban.

In order to get information on the origin of chromosome 18 aberrations trisomy 18 cases were analysed as well as different chromosome 18 rearrangements. In total, their study population consisted of 100 trisomy 18 patients and their parents, 67 out of which have already been published. Additionally, seven families were analysed with structural aberrations of chromosome 18 including four patients with tetrasomy 18p. Determination of parent and cell stage of origin was performed by short tandem repeat typing (STR, microsatellites). These investigations revealed that the additional chromosomal material in the majority of the chromosomal 18 aberrations was maternal in origin (97/107). In most of the cases the nondisjunction occurred during maternal meiosis II. This was in agreement with findings of other groups. Thus, independently from the type of aberration, there was a predisposition of chromosome 18 for nondisjunction in maternal meiosis II. In this respect, chromosome 18 seemed to be unique among human autosomes. Furthermore, these results showed that molecular genetic analyses of chromosomal aberrations and their formation mechanisms were meaningful tools in genetic counselling situations: in 5 cases where cytogenetic investigations could not performed, the clinical diagnosis of Edwards syndrome could be confirmed by molecular findings. Thus, in these cases other genetic diseases with differing types of inheritance could be excluded from being the cause of the observed malformations. In a further structural rearrangement of chromosome 18, the origin could be determined as being mitotic, therefore a recurrence risk could be excluded for this couple.

Abnormalities in tooth morphology, structure and dentition in two children with chromosome aberrations. Translocation trisomy 13 and trisomy 21.

PURPOSE: Dental malformations due to chromosomal trisomies are rarely described and need an intensive cooperation between pediatricians, orthodonticians and human geneticists to enable the collection of data and to extend the investigations on specific parameters of the teeth. RESULTS: Here we present tooth studies of two children with trisomies 13 (Pätau-syndrome) and 21 (Down-syndrome): the dentition, the tooth morphology and the structure as well as the composition were investigated over a period of six years. Both male patients showed a delayed and abnormal dentition. Morphologic and structural changes compared to the general population were also detectable; whereas, the composition of the teeth was unchanged in enamel, dentin, and the border between them. CONCLUSIONS: The abnormalities in all parameters investigated were more pronounced in the patient with Pätau-syndrome than in the child with Down-syndrome.

Sperm analyses, genetic counselling and therapy in an infertile carrier of a supernumerary marker chromosome 15.

PURPOSE: A supernumerary marker chromosome (SMC) was analysed after lymphocyte culture of a patient with oligoasthenoteratozoospermia (OAT) before ICSI treatment. MATERIAL AND METHODS: By additional molecular cytogenetic investigations the marker could be identified as a heterochromatic derivate of chromosome 15 [karyotype: 47,XY,+der(15)]. RESULTS: Sperm analyses by interphase FISH showed a normal monosomy 15 in 82% and an additional marker in 17% of the cells. In spite of these findings a pregnancy could not be induced. The brother of the patient showed the same chromosome abnormality and an OAT-syndrome as well. CONCLUSIONS: ICSI-treatment lead to a normal pregnancy and to the birth of a healthy boy. The genetic risk factors of both marker carriers are analysed in detail.

Global brain dysmyelination with above-average verbal skills in 18q- syndrome with a 17 Mb terminal deletion.

BACKGROUND: Patients with the karyotypic finding of a terminal deletion in the long arm of chromosome 18 (18q- syndrome) commonly display cerebral dysmyelination and developmental delay. To our knowledge, all reported cases characterized by molecular analysis who had no mental retardation as confirmed by neuropsychological testing had a chromosomal breakpoint within the two most distal bands, 18q22 or 18q23, leading to a deletion of 16 Mb or less. AIMS OF THE STUDY: It was the aim of this study to improve the karyotype-phenotype correlation in 18q- syndrome by thoroughly analyzing the deletion size and the mental and radiologic status in a 23-year-old woman with a terminal 18q deletion. We performed cytogenetic and molecular cytogenetic analysis, brain MRI, and extended neuropsychological testing. RESULTS: Molecular karyotyping revealed a 17 Mb deletion of terminal 18q with a breakpoint in 18q21.33 and no evidence for mosaicism. While brain MRI demonstrated severe global dysmyelination, the patient showed a neuropsychological pattern that allowed for normal psychosocial and job achievement. After delayed development in childhood, the patient caught up during puberty and showed normal verbal intelligence and skills at 23 years. However, visual, visual-spatial, visual-constructional, and executive functions were found to be severely impaired. CONCLUSION: Here, we present a patient with one of the largest terminal 18q deletions reported in an individual without obvious mental retardation. Our analysis extends the phenotypic spectrum for individuals with breakpoints in 18q21.33. In addition, this study highlights the fact that severe global dysmyelination may not be associated with general cognitive deficits.